A patient has a lesion in the right frontal eye field (FEF, Brodmann area 8). Acutely, the eyes deviate to the RIGHT. After 2 weeks, the deviation resolves. What is the mechanism underlying the ACUTE contralateral gaze deviation (towards the lesion side)?
- A Destructive lesion at FEF removes ipsilateral drive, leaving contralateral FEF drive unopposed, pushing eyes toward the lesion ✓
- B Irritative focus at FEF causing tonic activation driving eyes toward the lesion
- C Secondary compression of the ipsilateral PPRF causing contralateral gaze palsy
- D Simultaneous basal ganglia involvement suppressing the superior colliculus on the opposite side
Correct answer: A. Destructive lesion at FEF removes ipsilateral drive, leaving contralateral FEF drive unopposed, pushing eyes toward the lesion
Explanation
The frontal eye field (FEF) sends voluntary saccadic drive to the CONTRALATERAL PPRF (paramedian pontine reticular formation), causing contralateral gaze. When the right FEF is DESTROYED, its drive to the left PPRF is lost. The left FEF's drive to the right PPRF remains intact and unopposed, causing tonic deviation TOWARD the right (same side as the lesion). This is the classic 'looking at the lesion' deviation of destructive cortical lesions. Seizure (irritative lesion) causes conjugate deviation AWAY from the lesion. Recovery occurs as contralateral hemisphere takes over.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
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Written and medically reviewed by the StethoPrep medical team.